Hypoparathyroidism

Hypoparathyroidism is an uncommon condition in which the body produces abnormally low levels of parathyroid hormone (PTH). parathyroid hormone (PTH) is key to regulating and maintaining a balance of two minerals in the body — calcium and phosphorus.

The low production of PTH in hypoparathyroidism leads to abnormally low calcium levels in the blood and an increase of phosphorus in the blood.

Supplements to bring calcium and phosphorus levels into a normal range treat the condition. Depending on the cause of hypoparathyroidism, you'll likely need to take supplements for life. Sometimes parathyroid hormone replacement is needed if supplements alone are not enough to bring levels into a normal range.

Signs and symptoms of hypoparathyroidism are usually related to low calcium levels in the blood. Signs and symptoms can include:

• Tingling or burning in the fingertips, toes and lips
• Muscle aches or cramps in the legs, feet, stomach or face
• Twitching or spasms of muscles, particularly around the mouth, but also in the hands, arms and throat
• Fatigue or weakness

Other signs and symptoms associated with hypoparathyroidism can include:

• Painful menstrual periods
• Patchy hair loss
• Dry, coarse skin
• Brittle nails
• Depression or anxiety

If you have signs or symptoms associated with hypoparathyroidism, see your health care provider for an evaluation. Contact your health care provider immediately if you have a seizure or have difficulty breathing. These can both be complications of hypoparathyroidism.

Hypoparathyroidism occurs when the parathyroid glands don't produce enough parathyroid hormone. There are four small parathyroid glands in the neck behind the thyroid gland.

Parathyroid hormone controls the levels of calcium and phosphorus, so too little parathyroid hormone causes abnormal levels of:

• Calcium. This mineral is stored in bones and teeth and makes them hard. Calcium is also needed for muscle function, to help the nerves and brain work properly, and to control heart rhythm and blood pressure.
• Phosphorus. This mineral is found in all cells, but mostly in the bones. Phosphorus is needed to help the body create energy from food. Phosphorus also helps the muscles, nerves, heart and kidneys function.

Causes of hypoparathyroidism can include:

• Neck surgery. This is the most common cause of hypoparathyroidism. It develops after accidental damage to or removal of the parathyroid glands during surgery. Neck surgery may be done to treat conditions of the thyroid gland, or to treat throat or neck cancer.
• Autoimmune disease. In some cases, the immune system attacks parathyroid tissues as if they were foreign bodies. In the process, the parathyroid glands stop producing their hormone.
• Hereditary hypoparathyroidism. This form can result from either being born without parathyroid glands or with glands that don't work properly. Some types of hereditary hypoparathyroidism are associated with deficiencies of other hormone-producing glands.
• Low levels of magnesium in the blood. Low magnesium levels can affect the function of the parathyroid glands. Normal magnesium levels are required for normal production of parathyroid hormone.
• Extensive cancer radiation treatment of the face or neck. Radiation can result in destruction of the parathyroid glands. In rare cases, radioactive iodine treatment for hyperthyroidism may lead to hypoparathyroidism.

Factors that can increase the risk of developing hypoparathyroidism include:

• Recent neck surgery, particularly if the thyroid was involved
• A family history of hypoparathyroidism
• Having certain autoimmune or endocrine conditions, such as Addison's disease — which causes a decrease in the hormones the adrenal glands produce

Hypoparathyroidism can result in both reversible and irreversible complications.

Reversible complications

Complications due to low calcium levels that may improve with treatment include:

• Cramplike spasms of the hands and fingers that can be prolonged and painful.
• Muscle pain and twitches or spasms of the muscles of the face, throat or arms. When these spasms occur in the throat, they can interfere with breathing, creating a possible emergency.
• Tingling or burning sensations, or a pins and needles feeling, in the lips, tongue, fingers and toes.
• Seizures.
• Problems with kidney function, such as kidney stones and kidney failure.
• Abnormal heart rhythms (heart arrhythmias) and fainting, even heart failure.

Irreversible complications

Accurate diagnosis and treatment might prevent these complications or keep them from getting worse. But once they occur, taking calcium and vitamin D usually doesn't reverse the damage. Irreversible complications include:

• Hardening and changes in the shape of bones, and poor growth
• Delayed mental development in children
• Calcium deposits in the brain, which can cause balance problems, movement disorders and seizures
• Clouded vision due to cataracts
• Teeth that don't form properly, affecting dental enamel and roots, which can happen when hypoparathyroidism occurs at an early age when teeth are developing

There are no specific actions to prevent hypoparathyroidism. However, if you're scheduled to have thyroid or neck surgery, talk to your surgeon about the risk of damage to your parathyroid glands during the procedure. Your health care provider may choose to test your calcium, parathyroid hormone and vitamin D levels and have you begin taking supplements if needed before surgery.

Parathyroid autotransplantation may be an option to reduce the chances of postoperative hypoparathyroidism. The surgeon works to preserve parathyroid tissue in the neck during the procedure. However, occasionally the surgeon may need to move parathyroid tissue to another area of the body, such as the arm or the chest muscle. Transplanted parathyroid tissue does not always function.

If you've had surgery or radiation involving your thyroid or neck, watch for signs and symptoms that could indicate hypoparathyroidism, such as a tingling or burning sensation in your fingers, toes or lips, or muscle twitching or cramping. If they occur, your health care provider might recommend prompt treatment with calcium and vitamin D to minimize the effects of the disorder.